Why, after a Live Trace, when you Output to Swatches, do you always end up with a bunch of Unused Swatches? What are their purpose, assuming they have one? I see a lot articles explaining how to delete them, but nothing on why they're there to begin with.
live trace adds the swatches sampled from the original image you are tracing. for example if you have set it to 6 colour trace, it will add six colours to your swatch palette. it doesn't matter if they are used or unused, you can delete them from your swatch palette and it will not affect the trace.